Now comes the part where Tiger has to say he’s sorry — and until he does, we’re all pretending that no one knows how this will end. It’s one of the great false narratives left in American culture — the celebrity gone wrong at odds with a disillusioned public — and we’re at the turning point, the part where we await the grand confessional interview. That will be followed by some more hand-wringing — Is he really sorry? Has he suffered enough? Is this really any of our business? — and then we’ll all agree yes, yes and no and move on.

The only surprise here is that we fall for it every single time.

With rare exceptions — O.J. Simpson, Michael Jackson, a still-defiant Roman Polanksi and Chris Brown, and a cagey, particularly sleazy John Edwards — there are very few people and things the American public is not willing to forgive and forget.

Including, but not limited to: committing a hit-and-run (Halle Berry); an accusation of sexual assault (Kobe Bryant); getting indicted for murder (Ray Lewis); wife-beating, sexual assault, biting off a chunk of someone else’s ear (Mike Tyson); publicly musing that your opponent could get assassinated before Election Day (Hillary Clinton); making out with your brother, breaking up an A-list marriage (Angelina Jolie); running a dog-fighting ring (Michael Vick); cheating on your significant other with a hooker (Hugh Grant, Eliot Spitzer) or the nanny (Jude Law) or the staff (David Letterman), or an intern and many others (Bill Clinton); insider trading (Martha Stewart); stabbing a guy (Jay-Z); cheating on your longtime girlfriend with her young daughter, then marrying and having kids with her (Woody Allen); a DUI arrest, anti-Semitism (Mel Gibson); being a bad mommy (Britney Spears); throwing a phone at a desk clerk (Russell Crowe) or housekeeper (Naomi Campbell); calling your 12-year-old daughter a “thoughtless little pig” (Alec Baldwin); patronizing hookers (Charlie Sheen); jumping on Oprah’s couch and getting in an on-air fight with the likeable Matt Lauer over prescription drugs (Tom Cruise); being a douche (A-Rod).

So why do we do it? What sort of perverse gratification are we all getting from this, this pretend agony over moral failings, the false debates over the odds of survival?

First, says cultural anthropologist and University of Chicago professor Rick Shweder, we have to understand why we need to believe that some people, in particular celebrated ones, are better than the rest of us — that their accomplishments indicate a certain moral superiority.

“There’s a hierarchy in society,” he says. “There have to be role models that exemplify our values, so that those values are clear and can be passed on to the younger generation. Tiger was very good in that way. Now he looks like an immature, juvenile person. But the redemption narrative is powerful enough to overcome anything.”

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The Redemption Narrative: This is the part of the phenomenon that is uniquely American, taps into our late-19th century Calvinist roots. We can only have a redemption narrative if there is an action, or character failing, to be redeemed. “The idea that ‘I am good, we are good,’ is a fundamental notion of human agency,” Shweder says. “And where are you going to find the morality plays in our culture? In the sports pages and on Wall Street. The worlds of sports and finance can quantify performance and achievement. And there are rules.”

Ostensibly there are rules, but the only way to be shocked by rule-breaking is to pretend that everyone follows them. But lots of people don’t, and they tend to be high-achieving people with rare talents. In other words, people we both admire and envy, and wouldn’t mind maybe seeing cut down.

“It plays into our egalitarianism on one hand, our elitism on the other,” says Shweder. “We don’t like people being above the rules, but we also realize there’s a transgressive nature to creativity, and that can be sexual. Morality is often seen as conventionality holding back creativity.”

Or, to put it another way: “People are building you up to knock you down,” says veteran publicist and crisis consultant Howard Bragman. “You can come back again. We respect people who’ve been knocked down. We think it gives them character.”

Bragman thinks Woods should do “a cathartic interview” and, if he can, cry a little. “I always like my clients to cry,” says Bragman, who deems Mel Gibson’s post-arrest redemption interview one of the worst ever. “Mel didn’t sound convincing. He was sweating. He didn’t cry. Actors can always do a little tear.”

No matter: This week, Gibson announced that he’ll be directing Leonardo DiCaprio in a Viking epic, and will star in “How I Spent My Summer Vacation,” from a script he wrote about a criminal who survives prison in Mexico.

“The celebrity world is much more forgiving than the business world,” says Mike Sitrick, chairman and CEO of crisis management firm Sitrick Brincko.

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Most everyone who spoke to The Post brought up David Letterman’s handling of his extortion/adultery scandal as masterful, a script to be followed through the ages. “The real danger with Letterman was that he’s made fun of people for slimy, adulterous behavior,” says Mike Chapman, editor-in-chief of Adweek. “But he reacted so fast, just stood up and ’fessed up straightaway.”

“People love it when you take responsibility,” says Bragman. He thinks Letterman understands something Woods clearly did not: there is no such thing as privacy in the Information Age. “I tell my clients, ‘Information on the Internet is like herpes — it never goes away. It may lay dormant, but it never goes away.’ ”

Letterman’s accomplishment is even more remarkable in light of another variable: The public’s sense of betrayal is directly proportionate to the gap between perception and reality. Letterman deftly acknowledged as much in his confessional monologue: “I know what you’re saying: ‘I’ll be darned, Dave’s had sex?’” It was somehow never really shocking to learn Bill Clinton slept around, yet it kind of was to learn the same about John Edwards, who may have had the affect of a used-car salesman but also seemed to really be in love with his terminally ill wife.

In fact, there may be only two other public figures whose private transgressions could spark the kind of shock Woods has: Tom Hanks and Barack Obama. Woods, especially, has a lot in common with Obama: a mixed-race child of humble origins who became the first minority to break through a historically white institution, making everyone feel better about themselves in the process. It makes Woods’ challenge all the more difficult.

“Tiger, like Obama, symbolizes a certain form of American exceptionalism,” says Shweder. “We want Tiger, because of his [multi-racial] background, to be the perfect symbol of national unity. Which is a ridiculous thing to put on somebody.”

Shweder thinks that other issues of race, which are definitely part of this narrative’s subtext — Woods’ refusal to identify as black; his preference for white women; stereotypes about black men and sex — will never surface: “I think [following] the redemption script is most likely,” he says. “There is far too much to lose in allowing a racial discourse to go on. The only question is, what are the stages of his narrative?”

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Mike Sitrick thinks Woods should copy Bill and Hillary Clinton, who did a joint interview on “60 Minutes” in 1992, when allegations of Bill’s womanizing threatened to derail his campaign. For Woods, Sitrick suggests “two interviews, one print and one broadcast.” “60 Minutes,” preferably, to avoid the appearance of a softball interview, and a female journalist, “because she’d be seen as being sympathetic to the wife.”

If possible, “I would have had Tiger’s wife with him,” says Sitrick. “As with Hillary, who said, ‘Look, this is between us. It’s up to me to decide whether to stay with him, not the American people.’ And then you move on: He can always say, ‘I’ve said all I’m going to say about that on “60 Minutes,” and I’m not going to put my family through that again. I’ve already put my family through enough.’ ”

And if they divorce, as looks likely? “He can say, ‘I’ve already paid the highest price I can pay.’ ”

Woods’ only public-relations challenge, it seems, is to make people like him again. All of our experts agree that will happen, in part because it’s not very hard, in part because people want to like him again — a uniquely American trait — and in part because far too many people are invested in Woods’ continued dominance. “He’s gonna come back sooner or later,” says Anthony Crupi, senior editor at Mediaweek. “Sooner if his wife divorces him.”

There is already speculation that Woods will be back in time for the Masters in April, which may seem premature — but then again, we are living in an accelerated culture with a 24-hour news cycle, so April’s probably about right. It’s akin to the perverse satisfaction Yankees fans got out of finally being able to root for A-Rod, or the re-embrace of Mickey Rourke at last year’s Oscars, after nearly 20 years in exile. It would seem that Woods’ triumphant return is a foregone conclusion — and yet, the media will play along, expressing shock and awe at this amazing turn of events.

It wouldn’t be a satisfying narrative any other way. “The public is forgiving, but you have to take your lumps first,” says Sitrick. “Then they’ll take you back.” It’s really kind of S&M-ish, elevating people to unrealistic heights only to flagellate them for falling short.

One of the most interesting things about the Woods scandal was the amount of time it took for his first sponsor to drop him: Accenture waited till this past Monday, more than two weeks. For a bit there, though, it seemed the only retribution Woods would face would be at the hands of the people he hurt: not the public, not corporations, not the PGA — and it’s the latter that’s really suffering from Woods’ exile.

As much of a cliché as it may be to cite that famous Fitzgerald line — “There are no second acts in American lives” — it seems really fitting here, if only because it’s so patently false. There are second acts, and third acts, precisely because the public is complicit in writing them. Ted Kennedy had a second act after Chappaquiddick. Bill Clinton had a second act after his impeachment. Even Richard Nixon salvaged his post-impeachment legacy. John Quincy Adams served as a freshman congressman after having been president, and became a leader of the anti-slavery movement; William Howard Taft became chief justice of the Supreme Court after his presidency. Hillary Clinton lost to Barack Obama; she is now his secretary of state, but her approval rating is around 62%, whereas his has dipped just below 50%.

Tiger Woods will not have a problem.

Bragman, like Shweder, sees Woods’ redemption narrative as reflective of American exceptionalism, but of a more pragmatic, concrete kind: “I like that we forgive people,” he says. “I like that about our country; I think it’s one of the best things about it. We let you back in.”